C2MS12 — Improve Some Subject Specifics

See 6.2.2 Format of C2MS Subject Names in the 1.1 document. “An asterisk (*) can take the place of exactly one whole element but not a substring of an element.”

We want to allow asterisk to be used in a part of an element string, like:

".FO*-B*R-*AZ." matching to "FOO-BAR-BAZ"

There doesn't seem to be any reason that this couldn't work... we simply don't currently allow it. because it is not currently allowed and we would be now allowing it, it is backward compatible.

Also allow blank or empty subject elements and document the the use of FILL as only satisfying otherwise required elements. Make clear that you can't use blank for elements that are required. matching an empty would look like "foo..baz"... which would not match "foo.bar.baz".

In the OMG Leeds Meeting, we talked about idenifying a special character, instead of the special word FILL. Possible suggestions were = % ^ which would look like any of the following:

FOO.=.BAZ
FOO.%.BAZ
FOO.^.BAZ

But as we discussed using a special character in a subject name could cause problems and if so, the implementing component might have to substitute it with some text... I don't know... something like FILL.

So, for now, we are setting this aside, living with FILL and we can revisit at a time in the future.